It is often necessary to combine two sterile but separately contained medical solutions into a single solution before further use such as medical solutions administered to a patient. For example, many drugs are produced in concentrated solution or powdered form and are packaged in a glass vial sealed by a stopper. The drug and vial are sterilized in well-known manners such as radiation sterilization or heat sterilization by autoclaving. Likewise, a diluent solution may be packaged in a separate container such as a flexible bag and sterilized, for example, by radiation sterilization or autoclaving. Alternatively, a diluent solution such as sterile water may be produced on site by a water sterilizing device such as the low cost reverse osmosis sterile and pyrogen free water producing device of U.S. patent application Ser. No. 07/570,660, filed Aug. 20, 1990, entitled "Medical Drug Formulation and Delivery System and Reverse Osmosis Purification Device" which is hereby incorporated by reference.
It is difficult but necessary to transfer two separately contained solutions such as a drug and a diluent into a single container without introducing contamination. One example of sterilization during engagement of two components is shown by U.S. Pat. No. 4,431,424. In this arrangement a flexible casing containing a disinfectant surrounds at least one part of a first coupling element. The casing arrangement is provided with a seal to interact with an abutment on the second coupling housing during an introductory coupling movement between the components. The casing arrangement is capable of being rolled or pulled along the outside of the coupling element during the progressive engagement between the coupling components until they reach a fully engaged position allowing fluid passage.
The above described arrangement has two significant drawbacks. First, one of the coupling elements must be manufactured with the sterilizing agent attached. Second, the sterilizing agent will be intermixed with the two solutions.
The present invention is directed to a device which can be utilized with standard drug vials and flexible containers. Also the present invention is directed to a device which minimizes introducing the sterilizing agent into the mixed solution.